1. Field of the Invention
The present invention relates to a display apparatus, and more particularly, to a liquid crystal display (LCD) having a vertical alignment liquid crystal layer.
2. Description of Related Art
Since the liquid crystal display is limited by its principle of light emission, there remain some problems that urgently need mitigating. For instance, the range of the viewing angle in the liquid crystal display is too narrow. When a user views the liquid crystal display using a too large viewing angle, the display quality, such as contrast ratio, color saturation and luminance, is then lowered and is not as good as during normal viewing.
FIG. 1A is a schematic view showing the structure of a conventional vertical alignment liquid crystal display. Referring to FIG. 1A, this vertical alignment liquid crystal display (LCD) 100 mainly includes a thin film transistor (TFT) array substrate 110, a color filter (CF) substrate 120, a first polarizer 130, a second polarizer 140, and a vertical alignment liquid crystal layer 150.
Referring to FIG. 1A, the TFT array substrate 110 is disposed on the first polarizer 130, and the color filter substrate 120 is disposed over the TFT array substrate 110. The second polarizer 140 is disposed on the color filter substrate 120, and the vertical alignment liquid crystal layer 150 is disposed between the TFT array substrate 110 and the color filter substrate 120. The liquid crystal molecules in the vertical alignment liquid crystal layer 150 are rotated to different degrees according to the voltage difference between the TFT array substrate 110 and the color filter substrate 120, so that the vertical alignment liquid crystal display 100 displays images.
In order to enhance the display quality of the vertical alignment liquid crystal display, some optical films are added to further increase the viewing angle of the liquid crystal display.
FIG. 1B is a schematic view showing the viewing angle-contrast of a conventional vertical alignment liquid crystal display. Referring to FIG. 1B, the viewing angles in the base directions, such as top direction, bottom direction, left and right directions, of the vertical alignment liquid crystal display can be enhanced through the addition of optical films. However, as shown in FIG. 1B, since the viewing angle in the diagonal direction of the display surface still remains unsatisfactory, the conventional vertical alignment liquid crystal display still leaves much room for improvement. Therefore, how to entirely widen the viewing angles in any direction of the vertical alignment liquid crystal display to enhance the display quality thereof has become a major concern of the liquid crystal display.